'We were able to visualise every tissue, cell and growth line within the bony jaws, allowing us to study the development of the jaws and teeth,' said Ruecklin.

'We could then make comparisons with the embryology of living vertebrates, thus demonstrating that placoderms possessed teeth.'

The team studied Compagopiscis fossils, including those from the Museum collections, where there are many well-preserved and complete specimens.

Johanson adds, 'These wonderfully preserved fossils from Australia yield many secrets of our evolutionary ancestry but research has been held back waiting for the kind of non-destructive technology that we used in this study.'

'Without the collaborations between palaeontologists and physicists, our evolutionary history would remain hidden in the rocks'.